Door operator control mechanism and system



Aug. 10, 1965 w, KLAMP DOOR OPERATOR CONTROL MECHANISM AND SYSTEM FiledMarch 27, 1961 IN V EN TOR.

TOPN

United States Patent 3,199,857 DGGR (BPERATQR CONTRQL MEtCHANlSM ANDSYSTEM William Klamp, 223459 Hilliard Road, Rocky River, @hio Filed Mar.2'7, 1961, Ser. No. 98,641 12 Claims. (Cl. 268-59) The present inventionrelates to control means for reversing the direction of operation of amotor when a predetermined load is applied to drive mechanism beingoperated by the motor and, more particularly, to such a system which isparticularly suitable for use in opening and closing a door.

An important object of the present invention is to provide a new andimproved door operating mechanism which will be effective to reverse themotor driving the operator whenever the output element of a slip clutchconnecting the motor to the door changes from a normal rotatingcondition to a condition such as a stopped condition indicative of anoverload.

Another object of the present invention is to provide a new and improveddoor openating mechanism in which a centrifugal type switching meansoperated from the output element of a slip clutch interconnecting adrive motor and the door is operated to effect energization of thestarting winding for the motor to reverse the motor when the clutchslips, the mechanism being so constructed and arranged that the startingwinding does not remain energized in the event that the output elementof the clutch never starts to rotate upon the starting of the motor orrotates at such a speed as to be incapable of actuating the centrifugaltype switching means.

Another object of the present invention is to provide a new and improveddrive mechanism in which a reversible motor drives the input element ofa slip clutch having its output element connected to drive a load, andin which a centrifugal-1y operated mechanism rotated with the outputelement of the clutch is adapted to control the motor upon the slippingof the clutch, but is ineffective to effect a control of the motor untilthe output element of the clutch has been driven at a predeterminedspeed by the motor and then falls to a speed lower than a predeterminedspeed or stopped.

A further object of the present invention is to provide a new andimproved door operator in which a centrifugal switch type mechanism isactuated to reverse the drive motor when the output element of a slipclutch interconnecting the motor and door is stopped in response to anabnormal load applied thereto and while the motor is operating in a doorclosing direction, and in which the motor is a single phase motor andthe centrifugal switch mechanism closes contacts in the starting circuitto energize the starting winding and in which the starting winding isde-energized when the motor starts regardless of the condition of theoutput element of the clutch.

Yet another object of the present invention is to provide a new andimproved door operator control mechanism in which a centrifugal typeswitching mechanism is driven by the output element of a slip clutchconnecting the drive motor and the door, and in which the drive motor isa reversible motor which is reversed by changing the power connectionsto a winding normally energized during the operation of the motor and inwhich the centrifugal switching mechanism effects a reversing of themotor when the output element of the clutch stops rotating while themotor is energized to operate the door.

Another object of the present invention is to provide a new and improveddoor operating mechanism in which a reversible motor drives the doorbetween open and closed positions through a slip clutch and whereincentrifugal switching mechanism driven by the output element of theclutch is operated to reverse the direction of op- 3,19%,857 PatentedAug. 10, l65

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eration of the motor when the output element of the clutch stopsrotating while the motor is running, and which is so constructed andarranged to permit the load transmitted by the slip clutch to be finelyadjusted so that the clutch will only transmit the load normallyrequired to operate the door, thereby providing a control mechanismwhich is extremely sensitive to the presence of abnormal forces opposingmovement of the door.

The above objects and others are accomplished by providing a dooroperating mechanism in which actuating means for stopping the motor fromrotating in its direction of operation when the output element of theslip clutch changes from a normal rotating condition to one indicativeof an overload is arranged so that the actuating means is not effectiveuntil the output element first obtains a predetermined speed in thedirection of operation and the rotation of the element is then changed,

' e.g., stopped, to a condition indicating overload. Centrifugalforce-responsive member is rotated from the output element of the slipclutch, and when the output element is rotated, the force-responsivemember moves away from its axis of rotation due to centrifugal force.When the output element is stopped, the element moves or returns to arest position and momentarily actuates control means during its returnmovement for reversing the motor if the motor is energized. In thepreferred embodiment, the centrifugal force-responsive member is carriedby the output element of the clutch and supported for radial movementwith respect to the axis of rotation of the output element and biased toa rest position from which it is moved as the output element is rotatedby the motor. A switch is disposed adjacent the centrifugalforce-responsive member and a one-way actuating connection is providedbetween the member and switch so that the switch is momentarily actuatedto momentarily make a circuit for reversing the motor as the centrifugalforce-responsive member is returned to its rest position.

Further objects and advantages of the present invention will be apparentfrom the following detail description of the preferred embodimentthereof made with reference to the accompanying drawings forming a partof the specification and in which:

FIG. 1 is a view, somewhat schematic, of a door operator embodying thepresent invention;

FIG. 2 is a sectional view taken approximately along line 22 of PEG. 1;

FIG. 3 is an end view of that part of the apparatus shown in FIG. 2;

FIG. 4 is a circuit diagram which may be used with the operator shown inFIGS. l3; and

FIG. 5 is a modification of the circuit diagram of FIG. 4.

While the present invention is susceptible of various constructions andmodifications and of use where it is desired to reciprocate a memberbetween limit positions, which may be arbitrarily designated as open andclosed positions, it is particularly useful when embodied in an operatorfor opening and closing a door, such as a garage door, or other closure.Referring to the drawings, the present invention is illustrated asembodied in an operator of a conventional type which need not bedescribed in detail. Suflice it to say that a door 1% is operatedbetween open and closed positions by a door operator 11 which includesan endless chain 12 having upper and lower runs 13, 14, respectively,the chain 12 being supported for movement through an endless path byspaced sprockets 15, 16. The sprocket 15 is secured to a shaft 15adriven by a reversible motor 17 which is operated in one direction toopen the door and in the opposite direction to close the door.

A carriage 18 is fixed to lower run 14 of the chain 12. The carriage 13is connected to the door It) by a link 21 3 so that reciprocation of thecarriage 18 along the bottom run of the endless chain 12 will cause thedoor It) to open and close.

The upper run of the chain 12 has a limit lug 25 thereon which engages aleaf spring 26 when the motor 17 has been operated to move the carriageto the left, as viewed in FIG. 1, to a position where the door is fullyopened. The leaf spring 26 is supported at the right-hand end of theupper run, as viewed in FIG. 1, and is insulated from its support. Thelimit lug 25 is also adapted to engage a leaf spring 27, which issupported at the left-hand end of the upper run 13 and which isinsulated from its support, when the motor 17 has been operated to movethe carriage 18 to the right to a position where the door ft) is closed.The engagement of the lug 25 with either the leaf spring 26 or the leafspring 27 will ground the particular leaf spring to tie-energize controlrelays and the power circuit for the motor in a manner to be describedhereinafter.

The motor 17 has a rotor shaft 30 which has a pulley 31 thereon whichconstitutes the driving pulley of a belt drive 32, for driving an inputelement or member 33 of a slip clutch 34. The slip clutch 34- includesan output element or member 35 which is connected to rotate a shaft 36connected to drive the sprocket shaft a. The connection between theshaft 36 and the shaft 15:: can be any conventional connection such thatthe shaft 36 stops when the door stops as it meets an obstruction.

The slip clutch 34 is a conventional type of slip clutch and includesthe input element 33 which has a hub 37 rotatably mounted on the shaft36 so as to be rotatable with respect thereto and a radially extendingflange 37a. A belt-receiving pulley 3'7!) is formed in the periphery ofthe flange 37a and the input element is rotated from the motor shaft 3bby the belt drive 32. The output element 35 of the clutch 34 has a hub4t which is keyed to the shaft 36 for rotation therewith and a radiallyextending flange 41 adjacent the radially extending flange 37a of theinput element 33. The hub 46 has a sleeve 42 slidable thereon but keyedthereto for rotation therewith and the sleeve 42 has a flange portion42a facing the flanges 37a, 41. A clutch plate 43 is splined to theinput element 33 and extends inwardly from the input element to-aposition between the flanges 42a, 41 and the flanges 41, 42a have clutchelements 44 thereon which cooperate with the clutch plate 43 to providea frictiontype clutch assembly. The sleeve 42 is spring-urged, by aplurality of springs 46, toward the flange 41 to apply a clamping forceto the clutch plate 43. The springs 46 are interposed between the outerend of the sleeve 42, the left-hand end as viewed in FIG. 2, and acollar 57 which is slidably keyed to the hub 4-0. The springs 46 arereecived in spring seats in the adjacent sides of the collar 47 and thesleeve 42 and are spaced circumferentially about the hub 49. A nut 48 isthreaded onto the outer end of the hub 46 and the side of the nut 48facing the collar 47 is recessed to provide a seat for a ball-bearing 59which has a race 49' fixed in the nut 48 and a race 49:: which extendsoutwardly from the side of the nut 43 facing the collar 47 so that itengages the collar 47. The ball-bearing accommodates relative rotationbetween the collar 47 and the nut 48. Adjustment of the nut 48 bythreading the nut onto the sleeve or backing it off from the sleeve willincrease or decrease the compression in the springs 46 to vary the forcewith which the sleeve 42 clamps the clutch plate 43 between thecooperating clutch elements 44. If the compression of the springs 46 isincreased by running the nut on the hub as, the clutch will transmitgreater torque before slipping, and if the compression in the springs 46is decreased by backing otf the nut 48, the clutch will transmit lesstorque before slipping. While the clutch 34 has been described inconsiderable detail, various types of conventional slip clutches whichwill provide overload pro tection by slipping when a predetermined loadis applied to the output element may be used insofar as the broaderaspects of the present invention are concerned.

It can now be seen that the clutch 3d can be used to provide overloadprotection in the event that the door it) meets an obstruction duringits closing movement which would apply more than a normal load to thedoor it The torque which the clutch 34 will transmit before slippage isadjusted by adjusting the nut 48 and, preferably, the nut 48 is adjustedso that the clutch will slip if a force is called for which is greaterthan that normally necessary to effect a closing of the door it). Itwill be noted that since the clutch 34 will slip, the motor 1'7 is notstalled and the danger of burning out the motor due to stalling and thedrawing of large currents is minimized.

It is desirable, however, to reverse the door it when it is closing andthe clutch 34 slips and rotation of the shaft 36 stops, as when the doormeets an obstruction. To this end, the sleeve 42 has a centrifugalforce-responsive memer 53 mounted on a rod 54 extending radiallyoutwardly from the hub of the sleeve 4-2 parallel to the outer side ofthe flange 42a. The centrifugal force-responsive member 53 isspring-urged inwardly to a normal or rest position shown in the drawingsby a spring 55 disposed about the rod 54 and abutting the member 5'3 atone end and a lug 56 which extends outwardly from the flange 420 at theother end. The rod 54 has its radially outermost end supported in thelug 56. When the output element 35 is rotated, the centrifugalforce-responsive member 53 will move radially outwardly against theaction of the spring 55' due to centrifugal force, and when the rotationof the output element 35 stops, as when the door meets an obstruction,the spring 55 will urge the member 53 to the position shown in FIGS. 2and 3. A switch 57 is fixed to the flange 42a adjacent the member 53 andthe switch 57 is adapted to be actuated by movement of a pivoted lever58 in a counterclockwise direction about its pivot as the lever isviewed in FIG. 3. The lever 58 has an arm 60 pivoted to the outer endthereof and the arm 6%) has a portion 69a which abuts the lever 58 andprevents counterclockwise movement of the arm 6! about its pivotrelative to the lever 58. A conventional hinge spring may be used tourge the arm 60 into engagement with the lever 58. Consequently, if thearm 69 is moved counterclockwise, the lever 58 will also be movedcounterclockwise to actuate the switch Stl. If, however, the arm 69 ismoved clockwise, it will pivot about its pivotal connection to the lever58 and the lever 58 will not be moved. The arm 69 has a roller 61rotatably secured in the outer end thereof and the roller 61 is disposedin the path of movement of the member 53 from its normal or restposition shown in FIG. 3, outwardly to its position to which it moveswhen the output element 35 is rotated to drive the door it) to an openor closed position. The arm 6a? is moved clockwise about its pivotalconnection to the lever 52'; by movement of the member 53 past theroller 61. When, however, the member 53 moves from its radiallyoutermost position to its rest position, the arm as is pushed in acounterclockwise direction to operate the lever 58 and to actuate theswitch 57 as the member 53 moves to its rest position. The member 53preferably has a bevelled surface 63 which facilitates the member 53riding past the arm and roller 6h, hit when moving outwardly and whichprovides a shoulder 64 for moving the arm 6t) in a counterclockwisedirection when the member 53 moves inwardly. From the foregoing, it canbe seen that the switch 57 is actuated whenever the output element 42 isrotating and is stopped.

The switch 57 is, in the preferred and illustrated embodiment, anormally open switch, which, when closed While the motor 17 is energizedto operate the door in a closing direction, effects a reversing of themotor. If the motor 17 is operating in a door closing direction and theoutput element 35 stops, it is indicative of the fact that the door 10has met an obstruction and the movement of the member 53 from anactuated position inwardly to its normal or rest position will operatethe switch 57 to effect a reversal of the motor 17 to operate the latterin a door opening direction. Electrical connection is made to one sideof the switch 57 by a brush and ring connection com prising a stationarybrush 65 and a ring as on the sleeve 42 but insulated therefrom. Theother side of the switch is grounded through the mechanism.

The motor 17 may be a single phase motor having a start winding which isde-energized after the motor has started. In this type of motor, severedamage can be done to the motor if the start winding is not de-energizedafter the motor starts. Referring to FIG. 4, the motor 17 is shownschematically as comprising a start winding 67 and a run winding 68. Thestart winding 67 has a terminal 67a connected to one side of the powersupply,-

designated as L1 in the drawings, through a centrifugal switch '70 whichmay be the conventional switch commonly built into the rotor of thistype of motor. The centrifugal switch 70 is closed when the motor is atrest and is opened after the motor has started to de-energize the startwinding. The contacts of switch 70 are paralleled by the normally opencontacts '71 of a reversing relay '72 so that, if the relay 72 isenergized, a circuit will be completed for energizing the start winding67. The start winding has a second terminal 67b which is connected tothe other side of the power supply, designated in the drawings by L2.

The direction of operation of the motor 17 is controlled by controllingthe phase of energization of the run winding with respect to theenergization of the start winding.

. The run winding 63 has a terminal 68a which can be connected to Llthrough normally open contacts 73-OP actuated by an Open relay coil74-01 or to L2 through normally open contacts 75-0 actuated by a Closerelay coil 76-0, and normally closed contacts 77-01 actuated by therelay coil 74-01 The run winding also has a terminal 63b which can beconnected to L2 through normally open contacts 73-OP actuated by therelay coil 74- OP, or which can be connected to L1 through a circuitincluding normally open contacts 8h-C actuated by the relay coil 76-0and normally closed contacts Sit-OP actuated by the relay coil 74-OP. Ifthe relay coil 74-OP is energized, the terminal 63a is connected to L1and the terminal 68b is connected to L2; and, if the relay coil 76- C isenergized, the terminal 68a is connected to L2. Since the startingwinding is always connected to the power supply in the same way, if therelay coil 74-0? is energized, the motor operates in one direction andif the relay coil 76-0 is energized, the motor 17 operates in a reversedirection. In the illustrated embodiment, the motor 17 operates in adoor opening direction when the relay coil 74-01 is energized. If boththe relay coil Wt-OP and the relay coil 76-0 are energized, the motor 17will also operate in a door opening direction since the circuit forenergizing the run winding to operate in a door closing directionincludes the normally closed contacts til-0P and 77-OP which will beopened by the energization of the relay coil 74-OP.

The open relay coil 74-OP and the close relay coil 76-0 are part of alow voltage control circuit for the motor 17, which control circuit isenergized from the sec ondary coil 85 of a step-down transformer 86. Thesecondary coil 85 has terminals 85a, 85b, with the terminal 85b beingconnected to ground. The Open relay coil 74-OP may be energized bydepressing an Open pushbutton switch 87 to connect one side of the relaycoil to the terminal 85a, the other side of the relay coil 74-01 beingconnected to ground. When the relay coil 74-OP is energized, it operatesits previously described cont-acts in the power circuit for the motor 17to elfect operation of the motor 17 in the direction to open the doorand also closes holding contacts 87-OP connected in parallel with theopen pushbutton switch 87 between the terminal 85a and the relay coil74-01 After the motor 17 has started,

the centrifugal switch 70 will open and the start winding will bede-energized.

The motor 17 may be operated in a direction to close the door bydepressing a Close pushbutton switch 88 to connect one side of the relaycoil 76-0 to the terminal a of the secondary coil 85, the other side ofthe relay coil 76-0 being connected to ground. When the pushbuttonswitch 88 is depressed, the relay coil 76-0 is energized to close itscontacts, hereinbefore described, in the power circuit for the motor toeffect operation of the motor in a direction to close the door and therelay coil 76-0 also actuates self-holding contacts 90-0 connected inparallel with the Close pushbutton switch 8 to form a holding circuitfor the relay coil 7 6-0.

The relay coils 74-OP, 76-0 are de-energized when the door reaches itsopen or closed limit position by the engagement of the lug 25 witheither the leaf spring 26 or the leaf spring 27 to short-circuit theenergized coil causing it to drop out, opening its contacts in thecircuit for the run winding and also its holding contacts in parallelwith the corresponding push'button switch for energizing the coil. Theleaf springs 26, 27 are connected to the sides of their respective coilsconnected to the terminals 85a, and the lug 25 is connected to terminal85b through ground. The operation of the motor 17 may also be stopped atany time by depressing a pushbutton switch 91 which short-circuits thesecondary coil 85 and causes the relay coils 74-01, 76-0 to drop out ifeither or both are energized. The release of the switch 91 will notreenergize the relay coils 76-0, 74-01 since the self-holding contacts87-OP, 9 -0 will be open.

In the preferred and illustrated embodiment, when the clutch 34 slipsand the output element 35 stalls while the door is operating in a doorclosing direction, the relay coil 72 is energized to reverse the motor17. The relay coil 72 is connected in a series circuit with the switch57, the series circuit being connected in parallel with the relay coil76-0. The switch 57 has normally open contacts 57a so that normally therelay coil 72 will not be energized when the pushbutton switch 88 isdepressed to energize the relay coil rec to operate the motor 17 toclose the door. If the door closing operation is normal upon theenergization of relay coil 76-0, the motor will rotate the outputelement 35 of the clutch 34 to drive the door iii in a closing directionand the centrifugal force-responsive member 53 will move outwardly pastthe arm at to a position in which it is held by the centrifugal force.It the door now meets an obstruction, the output element 35 of theclutch 34- will stall and the clutch will slip so that the motor 17continues to run and the switch 76) remains open. The stalling of theoutput element 35 will cause the member 53 to be moved inwardly underthe action of spring 55 to actuate the switch 57 to close its normallyopen contacts 57a. Since the holding contacts 9tB-0 have been closed bythe energization of the coil 76-0, the closing of the contacts 57a willeffect energization of the relay coil '72 and this will, in turn, closethe normally open contacts 7]. in parallel with the centrifugal switch7% to energize the start winding. The relay coil 72 also has contacts 93in parallel with the Open pushbutton switch 87 so that, when the relaycoil 72 is energized, the relay 74-0]? is energized to reverse theconnections of the run winding to L1 and L2 and this, together with theclosing of the contacts 71, causes the motor 17 to operate in a reversedirection. It will be noted that the relay coil 7 5-0 will remainenergized while the motor 17 is operated in a reverse direction, butthis has no effect on the circuit, since the normally closed contacts ofthe relay coil 74-01 in series circuit with the contacts 75-0 and fitl-Crender these circuits inelfective to energize the motor. The relay coil72 is also ineffective to maintain the contacts 71 closed to keep thestart winding energized since the contacts 57a are only closedmomentarily while the member 53 is moving to its rest position. Themomenassure that the reversing will take place. When the door reachesits up-limit position, the lug 25 engages the leaf spring 26,.short-circuiting the secondary coil 85 and cansing all energized relaycoils to drop out. At this time, the switch 57 will be actuated as themember 53 moves to its rest position, but the coil 72 will not beenergized since the lug 25 has caused the de-energization of relay coil7C opening contacts Qti-C through which the coil 72 is energized.Similarly, if the door completes its closing movement, the motor willnot be reversed when the member 53 moves to a rest position since relaycoil 7543 will have been dropped out by the lug 25 engaging springcontact 27 to open contacts git-C.

One disadvantage of the above-described circuitry is that the stopbutton 91 must be pushed if the direction of door operation is to bereversed while the door is opening or closing. This is true becausemerely reversing the energization of the run winding by energizing the il-OP coil when the door is operating in a one direction will notnecessarily effect a reversal of the motor unless a circuit is also madefor energizing the start winding. In the described circuitry, thecentrifugal switch 79 will be op n while the door is operating in a onedirection and the contacts '71 will also be open, since the relay coil72 is deenergized under normal conditions and the motor may have to bestopped to close switch 70 if it is to be reversed by pushing theswitches 87, 83.

In the preferred embodiment, the contacts 71 of relay 72 are not usedand the run winding of the motor is in series with a start relay coil 95which functions to close contacts in the circuit for energizing thestart winding to effect an energization thereof whenever the start relayis actuated (see FIG. Preferably, the start relay is a ditferentialcurrent type of relay which requires a predetermined current magnitudeto energize the relay, but which will not be affected by currents of alesser magnitude. As is shown in FIG. 5, the start relay coil may beconnected between the contacts 73OP and the contact 81OP, on one hand,and Lil, on the other hand, so that regardless of the direction ofoperation of the motor, the current for the run winding must traversethe start relay coil. The start relay is such that, while the motor isrunning, the current in the run winding will not effect an actuation ofthe relay. 1 have found, however, that when the connections of the runwinding to the power supply are initially made or interchanged as whenthe relay coil 74GP is energized while the motor is operating in a doorclosing direction, the current surge in the run winding is sufiicientlylarge to be used to actuate the relay and close its contacts 96 toconnect the terminal 67a to L1. The closing or" the contacts will effecta reversing of the motor upon the interchange of the connections and,when the motor has started running in the opposite direction, thecurrent will be insufficient to maintain the contacts as energized andthese contacts will drop out. If the start relay is used, it is notnecessary to provide the centrifugal switch "it? to open the startwinding after the motor starts since the starts relay 95 will operate toaccomplish this function. if, however, a commercial motor is being usedwhich has the switch '79, the contacts 95 of the start relay may merelybe connected in parallel with the centrifugal switch. The currents whichare initially drawn when starting the motor from rest will also causethe start relay to be actuated to close the contacts to energize thestart winding on starting from rest. If the switch 70 is used, the relay95 is only needed for the reversing operation.

It can be further seen from the foregoing that the centrifugalforce-responsive mechanism for controlling the motor is such that underno conditions will the start winding 67 remain energized if the motor isrunning, since either the switch '74 or the contacts 96, depending onthe circuit used, will be open and the switch 57 will not make anindependent circuit for energizing the starting winding.

The infinite adjustment provided by the nut 48 and the roller bearingassociated therewith enables the clutch 34 to be precisely adjusted sothat it will transmit only the normal force necessary to operate thedoor in a normal manner. It is further noted that, even if the clutch isadjusted too light so that when larger forces are required to operatethe door in a normal manner, the clutch slips, there is no maintainingof the starting winding in an energized condition and the motor will berelatively safe from damage, even if the circuit of FIG. 4 is used or ifexternal switching is utilized to reverse the connections to the startwinding each time the motor is started. One of the worst conditionswhich can be met in door operation is when a door is opened a smallamount as when it is operated to allow air to enter or to allow theingress or exit of an animal. The door is lifted only a small distancefrom a closed position and, when the motor is started to close the door,the motor must operate against the conventional springs which arenormally tensioned at this point to facilitate the opening of the door.The forces required can be quite large and, if the clutch is set on thelight side, the output element 35 might never be rotated. Accordingly,if a circuit is used which relies upon the rotation of the outputelement of the clutch to open the starting winding circuit, the startingwinding would not be opened and the motor might suffer severe damage.

As mentioned above, the present invention may also be used with a singlephase motor where the movement of the door or part of drive mechanismeffects a reversal of the connections of the start winding to the powersupply after each motor start so that the direction of operation of themotor is reversed on the next start. Such a circuit is shown in myUnited States Patent No. 2,887,311 and in this type of circuit theswitch 57 need only be connected in parallel with the centrifugal switchin series with the start winding and which normally operates tode-energize the latter.

In the mode of operation described above, the switch 57 effects theenergization of a reversing relay which effects a reversing of themotor. It will be appreciated that the reversing relay could be utilizedto make a shorting circuit across the secondary of transformer to dropout all energized control coils and efiects a stopping of the motor inresponse to the slipping of the latch rather than a reversing of themotor. If the switch 57 is used in this manner, the normally opencontacts of the switch 5'7 could themselves make the shorting circuitand the relay coil 72 eliminated. Furthermore, in a system whichutilizes a single phase motor with a start winding whose connections tothe power supply are reversed to change the direction of operation ofthe motor, the switch 57 need only effect the making of contacts inparallel with the normal centrifugal switch contacts associated with themotor. This conventional motor switch is shown in FIGS. 4 and 5 as theswitch 7t and in the described type of system, which is fully disclosedin the aforesaid United States patent, the normally open contacts of theswitch :77 can be connected in parallel with the centrifugal motorswitch to complete a circuit about the motor switch when the door meetsan obstruction and is to be reversed.

From the foregoing, it can be seen that the present invention provides anew and improved mechanism and control circuit for stopping theoperation of the motor in one direction when the output el ment of aslip clutch interconnecting the motor and the load slips to indicate anoverload on the clutch, the system being such that a single phase motorcan be used without danger of maintaining the starting winding energizedand such that a motor which is reversed by changing the connections ofthe run winding can also be used in the system.

While the preferred embodiment of the present inven tion andmodifications have been described in considerable detail, it is herebymy intention to cover all modifications, constructions, and arrangementswhich fall within the ability of those skilled in the art and Within thescope and spirit of the present invention.

Having described my invention, what I claim is:

l. A drive mechanism including a reversible motor and a slip clutchhaving a rotatable input element driven by said motor and a rotatableoutput element connected to drive a load, said clutch slipping and saidoutput element stalling when a predetermined load is applied to thelatter, control means for selectively energizing said motor to rotate ineither of its directions of rotation and including reversing means forreversing said motor and causing the latter to operate in one directionand conditioned to be effective when said motor is energized to operatein its other direction comprising first means responsive to the rotationof said output element and operated momentarily from a normal conditionwhich it has with said output element at rest or rotating to an actuatedcondition and returned to its normal condition when said output elementchanges from a rotating condition above a predetermined angular speed toone below that speed, said first means having said actuated conditiononly during the momentary operation thereof, and means responsive to themomentary actuation of said first means for energizing said motor tooperate in a reverse direction to said other direction.

2. A drive mechanism including a reversible motor and a slip clutchhaving a rotatable input element driven by said motor and a rotatableoutput element connected to drive a load, said clutch slipping and saidoutput element stalling when a load greater than a predeterminedmagnitude is applied to said output element, control means forselectively energizing said motor; a centrifugal forceresponsive memberrotated by the output element of said clutch and moved outwardly from arest position upon rotation of said output element and returned to saidrest position upon the stopping of said output element; first meanshaving a nonactuated condition when said element is at rest or rotatingcontinuously and responsive to the movement of said member andmomentarily operated to an actuated condition and returned to saidnonactuated condition in response to the movements of said memberoutwardly of said rest position and return in sequence, said first meanshaving said actuated condition only during the momentary actuationthereof, and normally open circuit means conditioned to be effectivewhen said motor is energized to operate in one direction and mademomentarily to be energized in response to the actuated condition ofsaid first means to elfect the operation of said motor in its directionopposite to said one direction.

3. A drive mechanism including a reversible motor and a slip clutchhaving a rotatable input element driven by said motor and a rotatableoutput element connected to drive a load, said clutch slipping and saidoutput element stalling when a load greater than a predeterminedmagnitude is applied to the output element of said clutch, a centrifugalforce-responsive member rotated by the output element of said clutch andmoved outwardly from a rest position upon rotation of said outputelement and returned to said rest position upon the stopping of saidoutput element, normally ineffective reversing means for effecting areversal of said motor when said motor is operating in one direction andincluding a circuit element operable to an actuated condition, circuitmeans responsive to a momentary actuation of said circuit element toeffect a reversal of said motor, and motion transmitting means operatedby the return movement of said member to effect a momentary actuation ofsaid circuit element, said circuit element being actuated for eifectinga reversal of said motor only during the momentary actuation thereof bysaid member and said motion transmitting means being a unidirectionalmotion transmitting means and responsive only to the return movement ofsaid member to eifect said momentary actuation of said element.

4. A drive mechanism as defined in claim 3 wherein said circuit elementis a switch having normally open contacts and said motion transmittingmeans comprises a one-way switch actuator engaged by said member as saidmember moves outwardly from the rest position and when said memberreturns to the rest position, said one-way actuator being operated bysaid member to actuate said switch only during the return movement ofsaid member.

5. A drive mechanism for repicrocating a closure member between open andclosed limit positions, said mechanism comprising a reversible motor; aslip clutch having a rotatable input element driven by said motor and anoutput element connected to drive said member, said clutch slipping andsaid output element stalling when the load applied to the latter exceedsa predetermined magnitude; and control means for said motor comprising afirst relay coil energizable to effect operation of said motor in onedirection and efi'ective to reverse said motor it running in its otherdirection when said relay coil is energized, a second relay coilenergizable to eifect operation of said motor in its said otherdirection, means for selectively energizing each of said coils,reversing means conditioned to be effective when said second coil isenergized and actuated to energize said first relay coil when saidoutput element stops rotating comprising first means normally in anon-actuated condition when said output element is stopped or rotatingresponsive to the rotation of said output element and momentarilyoperated to an actuated condition and returned to said nonactuatedcondition when said output element changes from a rotating conditionabove a predetermined angular speed to one below that speed, said firstmeans being in a nonactuated condition whenever said output element isbelow said predetermined speed, means responsive to the mo mentaryactuation of said first means to eifect the energization of said firstcoil and a reversing of said motor; and limit means for de-energizingsaid coils and rendering said reversing means ineifective when saidmember is moved to a limit position by operation of said motor in itssaid other direction.

6. A drive mechanism for reciprocating a closure member between open andclosed limit positions, said mechanism comprising a reversible motor; aslip clutch having a rotatable input element driven by said motor and arotatable output element connected to drive said member, said clutchslipping and said output element stalling when the load applied to thelatter exceeds a predetermined magnitude; and control means for saidmotor comprising a first relay coil energizable to effect continuousoperation of said motor in one direction to a limit position andeffective to reverse said motor if running in its other direction whensaid first relay coil is energized, a second relay coil energizable toeffect operation of said motor in its said other direction to a limitposition, means for selectively energizing each of said coils, reversingmeans conditioned to be elfective when said second coil is energized andactuated to energize said first coil when said output element stopsrotating comprising a centrifugal force-responsive member rotated by theoutput element of said clutch and moved outwardly from a rest positionupon rotation of said output element and returned to said rest positionupon the stopping of said output element and first means responsive tothe movements of said forceresponsive member and momentarily operated toan actuated condition and returned to a nonactuated condition inresponse to the movements of said member outwardly of said rest positionand return in sequence and having said non-actuated condition wheneversaid output element is not passing through the speed at which said firstmeans is momentarily operated, normally de-energized circuit meansenergized momentarily in response to the actuated condition of saidfirst means to effect the energization of said first relay coil, andlimit means for tie-energizing said second coil and rendering saidreversing means ineffective when said closure member moves to its limitposition in said other direction.

'7. A drive mechanism for reciprocating a closure mem- 1 1 her betweenopen and closed limit positions, said mechanism comprising a reversiblemotor, a slip clutch having a rotatable input element driven by saidmotor and a rotatable output element connected to drive said member,said clutch slipping and said output element stalling when the loadapplied to the latter exceeds a predetermined magnitude, said motorbeing a single phase motor and having a start winding and a run windingand a centrifugal switch for de-energizing the start winding after themotor starts, reversing means for reversing said motor in response tothe slipping of said clutch when said motor is operating in onedirection comprising first means responsive to the rotation of saidoutput element and momentarily operated to an actuated condition andreturned to a non-actuated condition when said output element changesfrom a rotating condition above a predetermined angular speed to onebelow that speed and additional means responsive to the momentaryactuation of said first means for energizing said motor to operate in areverse direction comprising contacts connected in parallel with saidcentrifugal switch and momentarily made in response to the momentaryactuation of said first means, said contacts being closed only duringsaid momentary actuation due to the change in speed of rotation of saidoutput element and limit means for stopping said motor and renderingsaid reversing means ineffective when said closure member moves to itslimit position in said one direction.

8. A drive mechanism as defined in claim 7 wherein said first meanscomprises a centrifugal force-responsive member rotated by said outputelement and a one-way motion transmitting means actuated by saidforce-responsive member and transmitting actuating motion only when saidmember is moving toward a rest position upon the stopping of said outputelement and said additional means is a circuit element operated by saidmotion transmitting means.

9. A drive mechanism for reciprocating a member between limit positions,said mechanism comprising a reversible motor; a slip clutch having arotatable input element driven by said motor and a rotatable outputelement connected to drive said member, said clutch slipping and saidoutput element stalling when the load applied to the latter exceeds apredetermined magnitude; said motor being a single phase motor having arun winding and a start winding, control means for said motor comprisingfirst and second relay coils operable to energize said run Winding withcurrents of opposite phase to effect operation in opposite directions toa respective limit position, a start relay of the differential currenttype energized by current drawn by the run winding and actuated by thecurrent surge occurring when said run winding is initially energized andwhen the phase of the energization of said run winding is reversed, acircuit for energizing said start winding including contacts actuated bysaid start relay to effect energization and de-energization of the startwinding when said start relay is respectively actuated and dropped out,said first relay coil overriding said second relay coil when both areenergized, reversing means conditioned to be efiective when said secondcoil is energized and actuated to energize said first coil when saidoutput element stops rotating comprising a centrifugal forceresponsivemember rotated by the output element of said clutch and moved outwardlyfrom a rest position upon rotation of said output element and returnedto said rest position upon the stopping of said output element and firstmeans responsive to the movements of said member and momentarilyoperated to an actuated condition in rei2 sponse to the movements ofsaid member outwardly of said rest position and return in sequence, andnormally tie-energized circuit means energized momentarily in responseto the actuated condition of said first means to effect the energizationof said first relay coil.

Zlti. A drive mechanism for driving a member, said mechanism comprisinga reversible motor operatively connected to drive said member, saidmotor being a single phase motor having a run winding and a startwinding, control means for said motor comprising first and second relaycoils operable to energize said run winding with currents of oppositephase to eifect operation in opposite directions, a start relay of thedifferential current type energized by current drawn by the run windingand actuated by the current surge occurring when said run winding isinitially energized and when the phase of the energization of said runwinding is reversed, a circuit for energizing said start windingincluding contacts actuated by said start relay to eiiect energizationand de-energization of the start winding when said start relay isrespectively actuated and dropped out, said first relay coil overridingsaid second relay coil when both are energized, reversing meansconditioned to be effective when said second coil is energized andactuatable to energize said first coil to effect a reversal of saidmotor.

11. A drive mechanism including a reversible motor and a slip clutchhaving a rotatable input element driven by said motor and a rotatableoutput element connected to drive a load, said clutch slipping and saidoutput element stalling when a predetermined load is applied to thelatter, control means for selectively energizing said motor to rotate ineither of its directions of rotation and including control means forstopping the operation of said motor when the motor is operating in onedirection and conditioned to be effective when said motor is operatingin its one direction comprising first means responsive to the rotationof said output element and operated momentarily from a normal conditionwhich it has when said output element is at rest and when said elementis rotating to an actuated condition and back to said normal conditionwhen said output element passes through a predetermined speed whenchanging from a rotating condition to a stopped condition, said firstmeans being in a non-actuated condition except at said predeterminedspeed,

and normally broken circuit means for stopping the operation of saidmotor in said one direction when made and made in response to themomentary actuation of said first means.

12. A drive mechanism as defined in claim 11 wherein said control meanscomprises a centrifugal force-responsive member rotated by said outputelement and a switch actuated momentarily by the movement of said memberwhen said output element stops rotating.

References ited by the Examiner UNITED STATES PATENTS 2,378,262 6/45Vallen 318267 2,502,167 3/50 Moore 3l8267 2,533,116 12/50 lenkins 268592,568,808 9/51 Johanson 26859 2,954,224- 9/60 Schneider et al. 268-592,992,378 7/61 Schneider 318-267 2,992,819 7/61 Jackson 26859 3,078,4672/63 Schaefer 318-475 CHARLES E. OCONNELL, Primary Examiner. GEORGE A.NINAS, JR., Examiner.

1. A DRIVE MECHANISM INCLUDING A REVERSIBLE MOTOR AND A SLIP CLUTCHHAVING A ROTATABLE INPUT ELEMENT DRIVEN BY SAID MOTOR AND A ROTATABLEOUTPUT ELEMENT CONNECTED TO DRIVE A LOAD, SAID CLUTCH SLIPPING AND SAIDOUTPUT ELEMENT STALLING WHEN A PREDETERMINED LOAD IS APPLIED TO THELATTER, CONTROL MEANS FOR SELECTIVELY ENERRGIZING SAID MOTOR TO ROTATEIN EITHER OF ITS DIRECTIONS OF ROTATION AND INCLUDING REVERSING MEANSFOR REVERSING SAID MOTOR AND CAUSING THHE LATTER TO OPERATE IN ONEDIRECTION AND CONDITIONED TO BE EFFECTIVE WHEN SAID MOTOR IS ENERGIZEDTO OPERATE IN ITS OTHER DIRECTION COMPRISING FIRST MEANS RESPONSIVE TOTHE ROTATION OF SAID OUTPUT ELEMENT AND OPERATED MOMENTARILY FROM ANORMAL CONDITION WHICH IT HAS WITH SAID OUTPUT ELEMENT AT REST ORROTATION TO AN ACUTATED CONDITION AND RETURNED TO ITS NORMAL CONDITIONWHEN SAID OUTPUT ELEMENTT CHANGES FROM A ROTATING CONDITION ABOVE APREDETERMINED ANGULAR SPEED TO ONE BELOW THAT SPEED, SAID FIRST MEANSHAVING SAID ACTUATED CONDITION ONLY DURING THE MOMENTARY OPERATIONTHEREOF, AND MEANS RESPONSIVE TO THE MOMENTARY ACTUATION OF SAID FIRSTMEANS FOR ENERGIZING SAID MOTOR TO OPERATE IN A REVERSE DIRECTIONNN TOSAID OTHER DIRECTION.